JP2002093762A - Grinding machine for wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding machine in which the finish thickness of ground wafers can be measured sheet by sheet in the grinding machine and recorded in a control mechanism of the grinding machine. SOLUTION: The grinding machine of wafer comprises an index table born by a rotatable shaft, n (n is an integer from 2 to 5) wafer chuck mechanisms disposed, at a constant interval, on concentric circles centered about that shaft, a controller for separating the index table into a wafer loading/unloading stage s1 and a polishing stage, a grinding wheel unit disposed above the chuck mechanisms at the position of the grinding stage, an elevating/lowering mechanism of the grinding wheel unit and a rotary mechanism of grinding wheel, an equipment for measuring the thickness of a wafer mounted on the chuck mechanism at the position of the grinding stage, and an equipment 300 for measuring the thickness of a wafer mounted on the chuck mechanism 107c at the position of the wafer loading/unloading stage s1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an index table capable of measuring the thickness and lot number of each ground wafer in a grinding machine and communicating with a storage unit of a control device of the grinding machine. The present invention relates to a bull type grinding device.

[0002]

2. Description of the Related Art As a device wafer back surface grinding apparatus, a grinding wheel unit supported on a plurality of spindle shafts is used to reduce the grinding time of a wafer, and a plurality of grinding wheels provided at equal intervals on the same circumference. Loading stage and grinding stage for index table with chuck mechanism
And an unloading stage to reduce the throughput time of the wafer in the grinding apparatus. For example, Japanese Patent Laying-Open No. 11-307489 discloses a grinding apparatus in which index tables are allocated to a loading stage / unloading stage, a rough grinding stage, and a finish grinding stage.

The etching mechanism 20 shown in FIGS. 4 and 5
In the grinding apparatus 1 to which a wafer loading cassette 101 is attached, (A) a wafer loading cassette 11 is provided on the left side.
7 on the right side, and a wafer unloading cassette 117
Are arranged in the front row as a pair, and (B) the wafer row is placed on the base.
The wafer temporary mounting table 106 is arranged at the rear of the loading cassette, and the wafer cleaning mechanism 113 is arranged at the rear of the wafer unloading cassette in the next row. (C) The center of the base at the rear of the temporary mounting table and the cleaning mechanism is cut out. An index turntable is provided at the location where the
The table 108 is provided with three wafer chuck mechanisms 107, 107, 107 rotatably at equal intervals around the axis of the table, and includes a wafer loading / wafer unloading stage s1 and a rough grinding stage. -Di
2. The table is sectioned into the finish grinding stage s3,
(D) In the rear row of the index table, a frame 111 erected from the base is mounted on a grindstone 11 suitable for each grinding zone.
A grinding wheel unit in which 1b and 111d are supported on spindle shafts 111a and 111c is provided corresponding to a wafer chuck mechanism located at each grinding stage, and (E) the front row of the pair of cassettes, the temporary mounting table, and the wafer. The lifting mechanism 103, a rotation driving mechanism, a wafer alignment measuring mechanism, and respective arms 115a and 115 are provided at substantially the center of the base between the next rows of the cleaning mechanisms.
b, 115c, an articulated robot 115 having a control mechanism for driving the wafers is erected, and the wafers on the temporary table are indexed into a wafer loading / wafer unloading.
An articulated robot 115 which can be transferred to the chucking mechanism of the loading stage s1 and which can transfer the wafer on the cleaning mechanism to a wafer unloading cassette;
(F) The wafer is transferred from a temporary mounting table having a wafer suction pad 112a rotatably provided about a pair of shafts provided on the left and right sides of a substantially central portion of a base provided with an index turntable. -Transfer pad 112 for transferring to chucking mechanism of loading / wafer unloading stage
A transfer pad 112 for transferring a wafer on a chuck mechanism of a wafer loading / wafer unloading stage to a cleaning mechanism, and (G) a screw rod provided on a frame 110 erected from a base in a horizontal direction. Cleaning mechanism 109b of movable chuck mechanism and dresser 109a of chuck mechanism
With a pair of

The above-mentioned grinding device 101 (however, the chuck mechanism provided on the index table is such that m = a, b, c)
There are three. ), The following steps are used to grind the wafer.

(1) Robot 115 provided on a base
The wafer is sucked from the wafer loading cassette 117 to the suction arm and is placed on the temporary mounting table 106. (2) The index turntable 118 is rotated 120 degrees, and then the wafer on the temporary table is transferred to the transfer pad 11.
Then, the wafer is transferred to the chuck mechanism a of the wafer loading / unloading stage s1 of the index table by rotating the transfer pad, and during that time, the wafer is transferred to the suction arm of the robot. Uehara
The wafer is sucked from the loading cassette and is placed on the temporary mounting table 106.

(3) Index turntable 11
8 is rotated 120 degrees and the chuck mechanism a
The chuck mechanism b is moved to wafer s2 and the wafer loading /
After moving to the wafer unloading stage s1,
Lower the first spindle shaft 111a and move the grindstone 1
11b is pressed against the wafer, and the chuck mechanism a and the first spindle shaft are rotated to roughly grind the wafer. Then, the first spindle shaft is raised, and during this time, the wafer on the temporary table is moved by the transfer pad 112. The wafer is transferred to the chuck mechanism b of the wafer loading / unloading stage s1 of the index turntable, and the wafer in the wafer loading cassette is placed on the temporary table using the robot 115.

(4) The index turntable is set to 1
After rotating by 20 degrees, the chuck mechanism a was moved to the finish grinding stage s3, the chuck mechanism b was moved to the coarse grinding stage s2, and the chuck mechanism c was moved to the wafer loading / wafer unloading stage s1. After that, the second spindle shaft 111c is lowered to press the grindstone 111d against the wafer, the chuck mechanism a and the spindle shaft are rotated to finish grind the wafer, and then the second spindle shaft is raised, During this time, the first spindle shaft is lowered to press the grindstone against the wafer, and the chuck mechanism b and the spindle shaft are rotated to perform rough grinding of the wafer. Indexing the wafer on the table with the transfer pad
The wafer is transferred to the chuck mechanism c of the wafer loading / wafer unloading stage of the table.
The wafer in the wafer loading cassette is placed on the temporary table using the robot 115.

(5) The index turntable is set to 1
By rotating the chuck mechanism by 20 degrees, the chuck mechanism a is used for the wafer loading / wafer unloading stage s1, the chuck mechanism b is used for the finish grinding stage s3, and the chuck mechanism c is used.
Is moved to the coarse grinding stage s2, and the wafer that has been finish-ground by the transfer pad is transferred to the cleaning mechanism 113 by the transfer pad 112, and after the wafer is cleaned, the arm is moved to the arm of the robot 25 in the etching mechanism 20. The wafer that has been subjected to finish grinding and cleaning is adsorbed, placed on a spinner 26 of an etching mechanism, and the wafer surface is etched, cleaned, and rinsed. The rinsed wafer is sucked by the suction arm of the robot 25 and stored in the unloading cassette 24. Next, the transport pad 112 is rotated so that the
The wafer on the wafer 06 is transferred to a chuck mechanism a of a wafer loading / wafer unloading stage of an index turntable, while the wafer is sucked by a suction arm of the robot 115 from a wafer loading cassette. Then, the wafer is placed on a temporary mounting table, during which the second spindle shaft is lowered to press the grindstone against the wafer, and the chuck mechanism b and the spindle shaft are rotated to perform finish grinding of the wafer. The first spindle shaft is raised, the first spindle shaft is lowered, and the grindstone is pressed against the wafer, and the chuck mechanism c and the spindle shaft are rotated to perform rough grinding of the wafer.
Raise the second spindle axis.

(6) One index turntable
The chuck mechanism b is rotated by 20 degrees and the chuck mechanism b is moved to the wafer loading / wafer unloading stage, and the chuck mechanism c is rotated.
Is moved to the finish grinding stage and the chuck mechanism a is moved to the coarse grinding stage, and the wafer that has been finish-ground by the transfer pad is transferred to the cleaning mechanism, and the wafer is cleaned. The wafer that has been subjected to finish grinding and cleaning is adsorbed, placed on a spinner 26 of an etching mechanism, and the wafer surface is etched, cleaned, and rinsed. The rinsed wafer is sucked by the suction arm of the robot 25,
It is stored in the unloading cassette 24. Then, the transport pad 112 is rotated to hold the wafer on the temporary mounting table 106 as a chuck mechanism b for a wafer loading / wafer unloading stage of an index turntable.
Then, the wafer is sucked from the wafer loading cassette to the suction arm of the robot, and the wafer is placed on the temporary mounting table. Meanwhile, the second spindle shaft is lowered to press the grindstone against the wafer. Then, the finish grinding of the wafer is performed by rotating the chuck mechanism c and the spindle shaft,
Then, raise the second spindle shaft,
The first spindle is lowered to press the grindstone against the wafer, and the chuck mechanism a and the spindle are rotated to roughly grind the wafer, and then the first spindle is raised.

(7) The index turntable is set to 1
Rotate the chuck mechanism 20 by 20 degrees to move the chuck mechanism c to the wafer loading / wafer unloading stage.
Is moved to the finish grinding stage and the chuck mechanism b is moved to the coarse grinding stage. The wafer, which has been finished and ground by the transfer pad, is transferred to the cleaning mechanism, and the wafer is cleaned and rinsed. The wafer which has been finished and cleaned is adsorbed to the spinning system, and the wafer is rotated by an etching mechanism spinner 26.
And the wafer surface is etched, cleaned and rinsed. The rinsed wafer is sucked by the suction arm of the robot 25 and stored in the unloading cassette 24. Then, the transfer pad is rotated to transfer the wafer on the temporary table to the chuck mechanism c of the wafer loading / unloading stage of the index table, while the suction arm of the robot 115 is held. Then, a wafer is sucked from a wafer loading cassette, and the wafer is placed on a temporary table. During this time, the second spindle shaft is lowered to press the grindstone against the wafer, and a chuck mechanism a
Then, the finish grinding of the wafer is performed by rotating the spindle shaft, then the second spindle shaft is raised, and the first spindle shaft is lowered to press the grindstone against the wafer, and the chuck mechanism b and the spindle The shaft is rotated to roughly grind the wafer, and then the first spindle shaft is raised.

(8) Hereinafter, the rotation of the index turntable, the finish grinding and cleaning of the coarsely ground wafer, the etching of the wafer, and the unlocking of the etched wafer.
Steps (5) to (7) of storing in a loading cassette, transferring a new wafer to a wafer loading / unloading stage to a chuck mechanism, and rough grinding of a wafer are repeated. The cleaning mechanism 109 of the chuck mechanism
b and the dresser-109a of the chuck mechanism can be moved up and down,
In addition, it can move in the left-right direction, descends when there is no wafer on the temporary table, and cleans or dresses the chuck. During wafer grinding, the thickness of the wafer being ground is reduced to a two-probe in-process gauge 219,220.
Is transmitted to the recording unit (RAM) of the control unit (CPU) of the grinding apparatus.

In FIG. 4, reference numeral 21 denotes a shutter mechanism provided on a partition wall of the grinding apparatus 101 and the etching mechanism 20 for opening and closing an opening for transferring a wafer. 35 is also a shutter mechanism.

A polishing mechanism may be used instead of the etching mechanism (see Japanese Patent Application No. 11-111250). Also, the loading stage and the unloading stage of the index table may be distributed to different chuck mechanisms.

The fluctuation in the thickness of the ground wafer is as follows:
Device manufacturing manufacturers usually require 1.5 μm or less or 1.0 μm or less. In a conventional grinding apparatus, a wafer after grinding is extracted from a cassette and the finished thickness of the wafer is measured in a separate room. Was. That is, the thickness of all the ground wafers is not measured on the mass production line in the grinding machine, and when it is necessary to measure the thickness of all the ground wafers, the ground wafers stored in the cassette must be measured. They were carried to an inspection room where the thickness of the wafer was measured.

[0015] In the grinding apparatus shown in FIG. 4, the second grinding wheel chuck mechanism corresponding to two probe type in-process gain - it has been measuring the thickness T _i of the wafer is ground in di 220.
Grinding device 10 from two-probe in-process gage 220
When the thickness of the wafer is transmitted to the recording unit (RAM) of the control device 1 by an electric signal, the thickness T ₀ of the ground wafer previously input to the storage unit (ROM) is compared with the calculation unit by the arithmetic unit. Is within the permissible error range, the grinding machine is instructed to stop cutting, the spindle shaft 111c that supports the grindstone is held at its height position, zero grinding is performed for 30 to 60 seconds, and then the grindstone is raised to grind the wafer. To end.

The thickness T _i ′ of the zero-ground wafer is:
Thickness T _i of the ground wafer when cut stop is instructed
0 to 1 μm thinner than. Therefore, that the thickness of the grinding wafer the value of T _i becomes possible be far apart the actual thickness of the wafer slightly.

[0017]

SUMMARY OF THE INVENTION According to the present invention, there is provided a grinding apparatus capable of automatically measuring the finished thickness of each of the finished wafers in a grinding apparatus and recording the measured thickness in a control mechanism of the grinding apparatus. Provide equipment.

[0018]

According to a first aspect of the present invention, there is provided a grinding apparatus for pressing a grinding wheel unit against the surface of a wafer attracted to a chuck mechanism, and rotating and sliding the wafer and the grinding wheel to grind the wafer surface. The grinding apparatus comprises an index table supported on a rotatable shaft, and n groups (where n is 2 to 5) provided at equal intervals on a concentric circle centered on the shaft center. A wafer chucking mechanism, an index table, a wafer loading stage,
A control device for dividing into a grinding stage and a wafer unloading stage, a grinding wheel unit provided above the chuck mechanism at a grinding stage position, an elevating mechanism and a wheel rotating mechanism of the grinding wheel unit, and a grinding stage A thickness measuring device for measuring the thickness of the wafer mounted on the chuck mechanism at the chuck position and a thickness measuring device for measuring the thickness of the wafer mounted on the chuck mechanism at the wafer unloading stage position. A grinding apparatus for a wafer, comprising:

By providing a thickness measuring device for measuring the thickness of the wafer mounted on the chuck mechanism at the position of the wafer unloading stage, the finished thickness T of each of the finished wafers is obtained. _i ′ can be automatically measured in the grinding device and recorded in the control mechanism of the grinding device.

According to a second aspect of the present invention, in the grinding apparatus, the grinding apparatus further includes a brush scrub cleaning device for cleaning a wafer mounted on a chuck mechanism located at a wafer unloading stage. A thickness measuring device for measuring the thickness of a wafer placed on a chuck mechanism at a wafer unloading stage position is attached to a protective cover of the brush scrub cleaning device.

When the index table is rotated by 360 / n degrees and the ground wafer is transferred to the unloading stage, the brush of the brush scrub cleaning device descends to attract the brush and the wafer. The rotation of the chuck mechanism cleans the ground wafer. Next, the brush is raised, the thickness measuring device is lowered, and the thickness T _i ′ of the finished wafer is measured.

According to a third aspect of the present invention, in the grinding apparatus, the thickness measuring device is a two-probe in-process gauge,
The information of the measured wafer thickness T _i ′ and lot number is transmitted to a recording unit of a control device of the grinding device.

One probe of the two-probe in-process gauge contacts the reference surface of the chuck mechanism surface, and the other probe contacts the upper surface of the ground wafer mounted on the chuck mechanism. The difference between the heights is the thickness T _i ′ of the ground wafer. The wafer lot number (cassette number, wafer shelf number in the cassette) and the thickness T _i ′ transmitted from the two-probe in-process gauge to the recording unit (RAM) of the control device of the grinding machine are calculated by computer. -Data can be read from the screen or output to paper.

According to a fourth aspect of the present invention, in the above-mentioned grinding apparatus, the wafer loading stage and the wafer unloading stage also use the same chuck mechanism of the index table. .

By using the same wafer loading stage and wafer unloading stage with the same chuck mechanism of the index table, the number of chuck mechanisms can be reduced by one, the grinding apparatus becomes compact, and the footprint is reduced. Can be taken small.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 shows a grinding / loading stage of an index table of the grinding apparatus shown in FIG. 4, in which the cleaning device 109b is replaced with a brush scrub cleaning device, and a ground wafer mounted on a chuck mechanism. Probe type in-process gauge for measuring the thickness of
2 is a partial top view of the grinding apparatus of the present invention, in which a jig is attached to a protective cover of a brush scrub cleaning apparatus, FIG. 2 is a front view thereof, and FIG. FIG.

In the grinding apparatus 101 shown in FIGS. 1 and 2, 107c is a chuck mechanism for a loading / unloading stage, 108 is an index table,
w is a wafer, 300 is a two-probe in-process gauge,
400 is a chuck mechanism dresser, and 500 is a brush scrub cleaning device.

In the chuck mechanism dresser 400, a ring-shaped ceramic dresser 401 is fixed to a substrate 402, and the substrate is supported by a rotating shaft 403 that rotates by rotation of a motor 404. Reference numeral 405 denotes an air cylinder for raising and lowering the chuck mechanism dresser.

The brush scrub cleaning apparatus 500 includes a substrate 502 on which the brushes 501 and 501 are fixed, a rotating shaft 503 for bearing the substrate, a cleaning liquid supply pipe 504, and the rotating shaft 50.
3 is provided with a motor 505 for driving the motor 3, a protective cover 506, and an air cylinder 507. Chuck mechanism dresser 40
0 and the brush scrub cleaning equipment 500
00, the frame 600 is engaged with a guide member 602 by an engagement body 601, and the guide member 602 has a structure capable of moving left and right on the rail.

The two-probe in-process gauge 300 is
Protective cover 506 for brush scrub cleaning equipment 500
Attached to. One probe 301a of the two-probe in-process gauge is in contact with the reference surface of the surface of the chuck mechanism 107c, and the other probe 301b is on the upper surface of the wafer w mounted on the chuck mechanism 107c. Touch The difference between the two heights is the thickness of the wafer. In FIG. 3, 302a,
302b is a terminal, 303 is a rod, 304 is an air cylinder, 305 is a receiving part, and 306 is a joining part.

The two-probe in-process gauge 300 is moved by moving the engagement body 601 on the rail 603.
By moving the air cylinder and operating the air cylinder to push the receiving portion with the rod, the support shaft (not shown) is pushed down obliquely, so that the probes 301a and 302b contact the reference surface of the chuck mechanism and the upper surface of the wafer respectively. Then, the difference between the two heights is transmitted as the thickness of the wafer to the recording unit (RAM) of the control device of the grinding device.

The cleaning and transfer of the wafer vacuum-adsorbed to the chuck 107 of the second grinding stage s3 ground by the grinding device 101 is performed through the following steps. (1) The index table 108 is rotated 120 degrees, and the chuck mechanism 107 of the second grinding stage s3 is moved to the wafer loading / unloading stage s1. (2) The scrub cleaning device 500 is mounted on the rail 603 at a position above the vacuum-adsorbed ground wafer in the stage s1.
Move up and then brush 5 for brush scrub cleaning equipment
01 is lowered until it comes into contact with the wafer surface, and the brush is rotated while supplying cleaning water to the wafer surface from the nozzle 504 to brush-scrub the ground surface of the wafer to wash away grinding dust and abrasive grains. During this time, the chuck mechanism 107 is rotating.
The brush may be rotated to lower the brush scrub cleaning equipment while supplying the cleaning water to bring the brush into contact with the wafer surface.

(3) After stopping the supply of the cleaning liquid and raising the brush scrub cleaning equipment 500, or after raising the brush scrub cleaning equipment and stopping the supply of the cleaning liquid, two probes are made on the upper surface of the cleaned wafer. Child type in-process gage 3
The two-probe in-process gage is lowered by moving the engagement body 601 on the rail 603 so that 00 comes, and then lowering the brush scrub cleaning device to reduce the wafer thickness (T _i '). Is measured, and the thickness is transmitted to the recording unit (RAM) of the grinding device (CPU) together with the cassette number, the address (order number) of the wafer in the cassette number, and the thickness.

The wafer is loaded into the cassette 1 by the robot 115.
When the chuck body of the s1 zone is emptied on the chuck mechanism of the s1 zone, the engaging body 601 moves to the left on the rail 603,
01 is lowered until it comes into contact with the chuck mechanism, and while the cleaning water is supplied to the wafer surface, the annular ceramic is rotated to wash the chuck surface and wash away grinding dust and abrasive grains. During this time, the chuck mechanism 107c is rotating. Chuck mechanism 107
After the c dresser, the chuck cleaning device 400 is raised, and a new wafer is transferred from the cassette to the chuck mechanism 107c by the robot 115.

As another embodiment of the grinding apparatus of the present invention, the following embodiment can be considered. One grinding wheel unit (n = 2) for wafer loading / unloading stage and grinding stage One for grinding wheel unit, wafer loading stage, grinding stage and unloading stage Grinding wheel unit (n =
3) Wafer loading / unloading stage, rough grinding stage, medium grinding stage, and finish grinding stage.
Three grinding wheel units (n = 4) Two grinding wheel units (n = 4) for wafer loading stage, rough grinding stage, finish grinding stage, and unloading stage -Three grinding wheel units (n = 5), including a loading stage, a coarse grinding stage, a medium grinding stage, a finish grinding stage, and an unloading stage

[0036]

According to the grinding apparatus of the present invention, the finished thickness of each of the ground wafers can be automatically measured one by one in the grinding apparatus, and can be stored as data in the storage unit of the control unit of the grinding apparatus. Can be stored.

[Brief description of the drawings]

FIG. 1 is a partial plan view of a grinding device.

FIG. 2 is a side view of the grinding device of FIG.

FIG. 3 is an explanatory diagram for measuring a thickness of a wafer during a grinding process.

FIG. 4 is a plan view of an index table type grinding device.

FIG. 5 is a perspective view of a known grinding device.

[Explanation of symbols]

 101 Grinding device w Wafer 107 Chuck mechanism 108 Index table 111a, 111c Spindle shaft 111b, 111d Grinding grindstone 112 Transfer pad 115 Transfer robot 117 Cassette s1 Loading / unloading stage s2 Rough grinding stage s3 Finish Grinding stage 300 Thickness measuring device 400 Chuck cleaning device 500 Brush scrub cleaning device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B24B 55/06 B24B 55/06

Claims (4)

[Claims] 1. A grinding device for pressing a grinding wheel unit against a surface of a wafer attracted to a chuck mechanism, and rotating and sliding the wafer and the grinding wheel to grind the wafer surface,
The grinding apparatus includes an index table supported on a rotatable shaft, and n (where n is an integer of 2 to 5) wafers provided at equal intervals on a concentric circle centered on the shaft center. A chuck mechanism, a controller for dividing the index table into a wafer loading stage, a grinding stage and a wafer unloading stage, and a grinding wheel provided above the chuck mechanism at a grinding stage position. Unit, a lifting mechanism and a grinding wheel rotating mechanism of the grinding wheel unit, a thickness measuring device for measuring the thickness of a wafer mounted on a chuck mechanism at a grinding stage position, and a chuck mechanism at a wafer unloading stage position A wafer grinding apparatus comprising a thickness measuring device for measuring the thickness of a wafer placed on a wafer. 2. The grinding apparatus further includes a brush scrub cleaning device for cleaning a wafer placed on a chuck mechanism located at a wafer unloading stage, and a brush scrub cleaning device at a wafer unloading stage position. 2. A wafer grinding apparatus according to claim 1, wherein a thickness measuring device for measuring the thickness of the wafer placed on said brush scrub cleaning device is attached to a protective cover of said brush scrub cleaning device. 3. The thickness measuring device is a two-probe in-process gage for transmitting information of the measured wafer thickness and lot number to a recording unit of a control device of a grinding device. The apparatus for grinding a wafer according to claim 1, wherein: 4. The wafer grinding apparatus according to claim 1, wherein the wafer loading stage and the wafer unloading stage share the same chuck mechanism of the index table. .